Evaluation of corneal symmetry after UV corneal crosslinking for keratoconus

Figures & data

Table 1 Demographic data of both groups, including sample size, age, gender, and Amsler–Krumeich classification of grading keratoconus

	Treated group	Untreated group
Sample size	n=18	n=6
Age (years)	26.35±6.49	29.83±7.03
Gender (ratio M:F)	Male 15/female 3 (5:1)	Male 5/female 1 (5:1)
Classification of keratoconus	2.063±0.5	2.15±0.4

Note: Data shown as mean ± SD and p-value.

Abbreviations: SD, standard deviation; M, male; F, female.

Table 2 Comparison of the corneal symmetry indices and asphericity measurement in both treated and untreated group through their scheduled visits

	Treated group					Untreated group
	Baseline (n=18)	1–3 months (n=9)	4–6 months (n=8)	7–9 months (n=6)	10–12 months (n=7)	Baseline (n=6)	1 year follow-up (n=6)
CCT (µm)	440.47±43.22	441.11±46.37	436.50±53.21	440±48.19	439.57±29.68	494.83±46.39	480.50±46.89
Maximum K-reading (D)	57.06±7.71	54.51±5.47*	60.07±8.30	58.65±8.77*	55.36±6.05	49.95±2.25	51.97±3.83*
Minimum K-reading (D)	52.54±5.90	50.84±4.39	55.43±8.38	53.57±5.86	51.46±4.97	47.46±2.14	49.41±4.04*
BCVA	0.39±0.39	0.41±0.23	0.21±0.21*	0.03±0.03	0.04±0.18	–	–
ISV	138.47±36.71	126.33±31.35*	157.77±40.44	154.83±45.78	121±30.08	97.16±29.10	107.83±31.85*
IVA	1.23±0.43	1.18±0.19	1.32±0.38	1.26±0.39	1.05±0.314	1.05±0.43	1.07±0.41
KI	1.37±0.12	1.35±0.13*	1.44±0.14	1.37±0.15	1.32±0.14	1.25±0.12	1.29±0.13*
CKI	1.16±0.09	1.13±0.05	1.20±0.10	1.23±0.10*	1.15±0.06	1.09±0.03	1.12±0.05*
IHA	52.69±35.21	42.87±37.22	39.95±35.25	18.46±12.30*	42.51±16.99	34.75±22.05	25.30±16.19
IHD	0.22±0.07	0.18±0.05	0.24±0.07	0.22±0.08	0.19±0.06	0.16±0.06	0.17±0.06
Rmin (mm)	5.14±0.71	5.36±0.56	4.83±0.73	4.82±0.86*	5.26±0.67	5.80±0.54	5.55±0.71*
BFS (mm)	5.89±0.32	6.00±0.22	5.80±0.32	5.90±0.31	5.96±0.11	6.13±0.26	6.05±0.29
BE (mm)	69.70±35.10	61.44±29.97	83.00±43.37	87.66±39.98	88.28±31.32*	40.17±15.30	52.17±24.54*
Asphericity 6 mm (Q-value)	−1.91±0.85	−1.78±0.74*	−2.30±0.94	−2.52±0.96*	−1.86±0.63*	−1.13±0.45	−1.45±0.67
Asphericity 7 mm (Q-value)	−1.68±0.76	−1.58±0.66*	−2.06±0.86	−2.16±0.87	−1.61±0.55*	−1.05±0.38	−1.36±0.53
Asphericity 8 mm (Q-value)	−1.50±0.65	−1.40±0.56*	−1.82±0.79	−1.87±0.77	−1.43±0.47	−0.87±0.32	−1.10±0.44

Notes:

* Statistically significant compared to baseline (p<0.05). Data presented as mean ± SD and p-value.

Abbreviations: SD, standard deviation; CCT, central corneal thickness; BCVA, best-corrected visual acuity; ISV, index of symmetrical variation; IVA, index of vertical asymmetry; KI, keratoconus index; CKI, central keratoconus index; IHA, index of height asymmetry; IHD, index of height decentration; R_min, minimum radius of curvature; BFS, best-fit sphere; BE, back elevation; Q-value, anterior corneal asphericity.

Figure 1 Changes in the anterior corneal surface asphericity over time in the treated group.

Figure 2 Correlation between BCVA and asphericity at 3 months in (A) in 6 mm ring, (B) in 7 mm ring and (C) in 8 mm ring.

Abbreviation: BCVA, best-corrected visual acuity.

Figure 3 Correlation between K_max and asphericity at 3 months in (A) in 6 mm ring, (B) in 7 mm ring and (C) in 8 mm ring.

Abbreviation: K_max, maximum K-reading.